People often wear noise-canceling or noise-attenuating headphones in busy and/or noisy environments such as offices, coffee shops, and libraries to block out distractions while they work or study. The headphones can be, for example, in-ear headphones (e.g., ear buds), on-ear headphones, or over-the-ear head phones. In many instances, the headphones provide a certain degree of passive noise attenuation by covering the wearer's ear canal. In addition, some headphones can provide active noise canceling by generating sound waves that are opposite to detected sound waves impinging on the headphones.
In some circumstances, noise attenuation and/or noise-canceling can be provided by items other than headphones. For example, some people have private office spaces and can close a door to block or attenuate outside noises. While noise-canceling or noise-attenuating devices, such as those described above, may enable the user to enjoy a distraction-free environment, the user may miss out on events around him while using such a device.